Chapter 7

Question 1

Absorption

Answer 1

refers to those photons that are attenuated by the body and do not reach the image receptor.
(PATIENT DOSE)

Question 2

Classical interactions

Answer 2

are also commonly known as COHERENT scattering or THOMSON scattering. In this scattering event the incident x-ray photon interacts with an orbital electron of a tissue atom and changes direction. DOES NOT REMOVE ELECTRON!!!!
(words in caps=remember)

Question 3

Compton scattering

Answer 3

In this interaction, an incident x-ray photon enters a tissue atom, interacts with an orbital electron (generally a middle- or outer-shell electron), and removes it from its shell. This interaction does three things. First, it ionizes the atom, making it unstable. Second, the ejected electron, called a Compton electron, or secondary electron, leaves the atom with enough energy to go through interactions of its own in adjacent atoms. Third, the incident photon is deflected in a new direction and is now a Compton scatter photon. (COMPTON=SCATTERING)(MAJOR SOURCE OF OCCUPATIONAL EXPOSURE)

Question 4

Differential absorption

Answer 4

is the difference between the x-ray photons that are absorbed photoelectrically and those that penetrate the body

Question 5

occupational exposure

Answer 5

caused by Compton scattering
(Compton=gang occupied)

Question 6

Pair production

Answer 6

The interaction occurs when the incident x-ray photon has enough energy to escape interaction with the orbital electrons and interact with the nucleus of the tissue atom. In this interaction, two particles are produced: a positron (positively charged electron) and an electron (may also be called a negatron)

Question 7

photodisintegration

Answer 7

the nucleus of the atom involved regains stability by ejecting a nuclear particle such as a proton, neutron, or alpha particle

Question 8

photoelectric interactions

Answer 8

as with Compton interactions, the tissue atom is ionized. In the case of photoelectric interactions, the inner-shell vacancy makes the atom unstable; to regain stability a characteristic cascade occurs, producing secondary x-ray photons.
(PATIENT DOSE)!!!

Question 9

photoelectron

Answer 9

an ejected electron. In these events the incident x-ray photon interacts with the inner-shell electron of a tissue atom and ejects it from orbit. In the process, the incident x-ray photon expends all of its energy and is totally absorbed

Question 10

radiolucent

Answer 10

Less dense structures that have a much lower probability of absorption

Question 11

radiopaque

Answer 11

Body structures that readily absorb x-rays

Question 12

secondary photon is

Answer 12

a characteristic photon

Question 13

Transmission

Answer 13

refers to those x-ray photons that pass through the body and reach the image receptor.